Traffic-controlling system



Dec. 11, 1928. 1,695,131

A. G. WILLIAMSON TRAFFIC CONTROLLING SYSTEM Original Filed Nov. 16. 1918 3 Sheets-Sheet 1 w v Canola e1 Dec. 11, 1928.

A. G. WILLIAMSON TRAFFIC CONTROLLING SYSTEM original Filed Nov. 16, 1918 3 Sheets-Sheet 2 3 vwemtoz 4' WM Dec. 11, 19 2s. 1,695,131

A. G. WILLIAMSON 1 TRAFFIC CONTROLLING SYSTEM -0ri ginal F e NOV- 1918 Sheets-Sheet 5 Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

ABBA G. WILLIAMSON, OF CARNEGIE, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH TRAIN CONTROL COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWARE.

TRAFFIC-CONTROLLING SYSTEM.

Application filed. November 16, 1918, Serial No. 262,797. R newed May 11, 1928.

The present invention relates generally to traffic controlling systems such are used in connection with trains, the traffic controlling means being either merely signals or retarding and stopping devices or both.

The main objects of the invention are to afford continuous control of the train in response to trafiic conditions, so that whenever traffic conditions change the control of the train will likewise change, and further to render the control unit of the train simple and easily applicable and of such a character that no contact between the electrical equipment of the train and that of the traflic rails is needed. The result is that, assuming" the track to be equipped, a foreign engine not belonging to the particular system in which it is desired to use it, can be equipped in a short time to coact with the existing track circuits. A further object of the invention is to retain the present two block danger zone, instead of a third or caution zone now generally used in train control systems. A still further object of the invention is the elimination of control line wires.

One feature of the invention centers around the use of an induced-current circuit and translating device in the train that is respon sive to traflic variations produced in the track circuit and which in turn varies the effective value of a charged circuit in the train, there being a traflic governing means under control of the charged circuit. In the embodiment of the invcnti on here disclosed, the direct current charged circuit is normally varied as to its characteristics by the induced-current circuit and its translating device, said induced current circuit and translating device ceasing to influence or affect the direct current when abnormal tratlic conditions arise, in, which event the traffic governing means move to a position indicating danger.

Other features of the invention will the specification proceeds.

In the accompanying drawings, the invention is disclosed in several concrete and preferred forms from which however changes can be made without departing from the scope of the invention.

In said drawings Figure 1 is a diagrammatic view of one form of the train-carried apparatus embodying the invention.

Figure 1 a detail of the release valve when in its released position.

appear the overlapping contacts; Fig. 5 showin the full up position, Fig. 6 the middle posltion and Fig. 7 the full down position.

In the embodiment shown, the train carries an induced-current circuit consisting here of induction coil 1, conductor 2, coils 3 and 4 of the translating device 5, conductor 6, condenser 7 conductor 8, back to coil 1. The

coil 1 is suitably attached to the train as shown and as close to the running rails as practical and is preferably wound on a laminated magnetic core located transversely of the rail length.

The translating device 5 is preferably constructed as follows: Coils 3 and 4 are mounted on the poles of a permanent magnet 9. The casing 19 is made of insulating material and supports, by means of terminal screws 11 and 12, a vibratory diaphragm-armature responsive to coils 3 and 4. Mechanically and electrically connected to diaphragm 10 is a metal button 16. Button 16 is carried by mica-diaphragm 17, the circumferential edge of which is clamped by cap 18 to the cup 13. Contained within cup 13 is a body of carbon granules. Associated with this body of carbon granules is front electrode 15 and back electrode 14. Front electrode 15 is electrically connected with metal button 16 and is free to vibrate owing to resiliency of mica diaphragm 17, and back electrode 14 is e1ectrically connected to terminal screw 20 and is held rigidly in position.

A. relay circuit is carried by the train and consists of the following elements :battery 21, wire 22, terminal screw 12, vibrating armature 10, metal button 16, front electrode 15, carbon granules, back electrode 14, stem of cup 13, terminal screw 20, wire 23, coil of the relay 24, wire and back to battery 21. The relay 24 is a common direct current polarized relay. The battery 21 is a one cell storage battery.

A magnet valve circuit is also carried by the train and consists of the following elements :battery 21, wire 22. wire 26, contact point 27., neutral armature 28, connection 29,

polarized armature 30, contact point 31, Wire 32, coil of the magnet valve 33, wire 34 and back to battery 21. The magnet valve 33 is arranged to display the semaphore indicator 35 in a proceed position Whenever its coil is energized, and the semaphore indicator 35 in a danger position whenever its coil is deenergized.

Associated With magnet valve 33 is brake valve 36 and release valve 37. The actionrof these valves is such that whenever the magnet valve is energized valve 38 is held seated against the brake pipe pressure and valve 39 is held open. Pressure thus flows from the brake pipe past valve 39 and through pipe 40 to piston chamber 41, of brake valve 36, forcing piston 42 against spring 43, to the right, seating valve 44 as shown. This seating of valve 44 prevents the brake pipe pressure from escaping through pipe 45 and out through port 46 of release valve 37 to atmosphere.

With magnet valve 33 tie-energized, pressure lifts valve 38 and. causes valve 39 to seat.

- Pressure is now shut off from chamber 41 and the latter is exhausted to the atmosphere through pipe 40, past valve 38 and by port 47 of magnet valve 33. Upon the exhaustion of chamber 41, valve 44 is forced open and the brake pipe pressure at once escapes and applies the air brakes of the train. It should be noted that the forcing open of valve 44 also closes small valve 48. The operator can stop the application of the air brakes by turning release valve 37 to its releasing position. (Figure 1.) However he can not affect the position of indicator 35. That is, the releasing of the air brakes is at the discretion of the operator but the displaying of the indication Danger or Proceed is beyond his control. It should be noted that the operator can not continually leave release valve 37 in release position for on the next energizing of the magnet valve, valve 44 being seated by pressure in chamber 41, valve 48 is forced open and the brake pipe pressure escapes through pipe 49 and port 50 of release valve 37, keeping the brakes applied. To prevent the gradual bleeding of the brake pipe and thus an application of the brakes of the train, the operator must turn release valve 37 back to its normal position. By this inter-relation of brake valve 36 and release valve 37 the operator is forced to take recognition of the receipt in the cab of both a danger and proceed indication.

The track is divided (Figure 2) into the customary blocks, and each block is supplied with a track relay and track transformer. The primary coils 101 of the track transformers are supplied with power from the genera-tor 51 over the supply wires 52 and 53.

When track relay 54 of block C is energized, rails 55 and 56 of block B are supplied with power from transformer secondary 57,

rail 55 being connected by Wire 58 to one terminal of transformer secondary 57 and rail 56 by Wire 59, armature 60, front contact 61 and Wire 62 to the other terminal of 57. The voltage of secondary 57 is relatively high and for the sake of description Will be considered to be of the value of 20 volts. Rail 55 is also connected to transformer secondary 63 by Wires 58 and 64; and when track relay 54 of block C is ole-energized, rail 56 is connected to secondary 63 by wire 59, armature 60, back contact 65 and wire 66. The voltage of transformer secondary 63 is relatively low and will beconsidered as of three volts. Transformer 63, having a value of three volts, is of the constant current type and is so designed that it never furnishes enough current to affect translating device 5, but transformers 57 and 78, having a value of twenty volts, furnish sufficient current to affect said device.

Track relay 67 of block B is connected to rail 55 by Wire 68; While the other terminal where it is not in contact with either back contact 73 or front contact 70. So also in respect to armature 75 of relay 67 there is no place in its movement where it is not in contact with either back contact 76 or front contact 77; that is, these armatures come into contact with their front contacts before they leave their back contacts. It is to be under stood that all ofthe track relays with which the system is provided function in the manner just described, with reference to 67.

The overlapping of contacts 70 and 73, of relay 67, is necessary as the current for its energization is carried through one or the other of these contacts. Likewise, the overlapping of contacts 77 and 76 is necessary so that there-will be no momentary break in the track circuit for the block in the rear (block A in this case) while relay67 is being picked up.

lVith relay 54 energized (blocks C and B both clear) the rails of block B will. be supplied with 20 volts from transformer secondary 57; however, the flow of current will not be excessive through relay 67 due to impedance 72. When relay 54 is de-energized (block C occupied and block B unoccupied), the track relay of block B will receive but 3 volts from secondary 63. The three volt current flowing through relay 67 is not sufficient to energize it to the extent necessary to attract 69 into contact With 70.

The three volts, flowing through the coil of relay 67 by Way of back contact 73, will thus not pass through impedance 72 but will be sufiicient to lift the armatures 69 and 7 5 ill to a partial-up position, that is to a position against a spring in a manner to be presently described. In this partial-up position armature 75 has been lifted sufficiently to be in contact with front contact 77 and has broken its contact with back contact 76. That is to say, the rails of block A are supplied with a voltage of 20 volts from transformer secondary 78. Or in other words, with block C occupied, block B is a caution block and block A a clear block. Going back to the partialup position of relay 67, in this partial-up position the armature 69 has not yet been lifted off its back contact.

The method of overlapping the relay contacts is shown in Figs. 5, 6 and 7 in connection with armature of relay 54 an example. As here shown armature 60 carries two springs 61' and Fig. 5 shows the armature in full up position, spring 61 being compressed against contact point 61 and spring 65 being out of engagement with con tact point 65. In Fig. 6 armature 60 is shown in mid-position with'spring 61 in engagement with contact point 61 and spring 65' in engagement with contact point 65. In 7 armature 60 is in full down position with spring 65 compressed against contact point 65 and with spring 61 out of engagement with contact point 61.

When block B becomes a clear blocl: by block C becoming a caution block and relay 67 thus supplied with 20 volts from the secondary 57, then armatures 69 and 7 5 will be lifted to a full-up position, in engagement with their front contacts only.

Let us assume that a train enters block B from block A and that block C is clear of all traflic and its relay 54 energized. The train upon entering block B will immediately shunt relay 67 and as the resistance of the wheel-axle shunt will be very low, the flow of current from transformer secondary 57 will be large. This heavy current will flow over this circuit, transformer secondary 57, along, let us say, wire 58, rail 55, wheel-axle shunt, rail 56, wire 59, armature 60, front contact 61, and wire 62. This alternating current flowing in the rails under the coil. 1 on the vehicle will induce a current in the coil 1, which will flow in the induced-current circuit on the vehicle.

This induced-current will have the same characteristic as the current in the rails. Arsuming that the rail current has a frequency of 60, the induced-current flowing in the .induced-current circuit on the vehicle will also have a frequency of 60, and, just as in a common telephone receiver, current in. coils 3 and 4 will effect a pull on vibrating armature 10 which will be caused to vibrate with the frequency of an alternating current, which we have taken as 60.

The front electrode 1.5 of the variable resistance device, being fastened to the armaturn 10, it is clear that the pressure on the carbon granules will vary between a maximum. and a minimum value as the armature 10 vibrates. If armature 10 vibrates 60 times in a second the resistance of the variable resistance device will likewise vary between a maximum and a minimum value 60 times per second, as the resistance of the carbon granules is proportional to the pressure placed upon them.

Vith a direct current flowing in the relay circuit on the train, and with armature '10 not vibrating the value of this direct current in the relay circuit will be constant and of a value, let us say, of one. Now with armature 10 vibrating, the current in this relay circuit will fluctuate between a maximum and a minimum value due to the fluctuating value of the resistance between electrodes 14 and 15, cau ed by the varying pressure on the carbon g anules. The minimum value of the current du ing the time armature 10 vibrates, will be, let us say, 0.5. Due to the selfinductance of the coils of relay 24, the pull on armatures 38 and 30, during the time armature 10 vibrates, will be equivalent to that of a direct current of the value of 0.5.

To correspond with 0.5 current value, when armature 10 is vibrating, polarized armature 30 of the relay 24:, is adjusted so that it will, always seek its right-hand position, as shown, and will be flipped to its left-hand position only when there is a direct current of the value of 0.6 or more flowing in the coils of the relay 24: and of a polarity as shown in the figure. Therefore, with armature 10 not vibrating, and the current in the coils of the relay 24 of the value of 1.0 it is evident that polarized armature 30 will be flipped to the left-h and position and the mag net valve circuit broken at the contact point 31., while with. armature 10 vibrating and the effective direct current in the coils of relay 24 of a value of only 0.5, polarized armature 30 will be in. its right-hand position and the magnet valve circuit will be complete.

As long as this condition exists armature 10 vibrating) magnet valve 33 is energized causing semaphore indicator 35 to display a proceed indication and brake valve 36 to hold closed valve 44; but if armature 10 ceases to vibrate, the current in the relay circuit at once rises to the value of 1.0, causing polarized armature 30 of relay 24; to be flipped. to the left-hand position, rupturing the magnet valve circuit when semaphore indicator 35 will display a danger indication and the brake valve will act to apply the air brakes. Therefore, a train entering block B when block C is clear, the heavy current in the rails under the coil 1 will generate in the coil 1 an induced current and this induced current in coils 3 and 4 vibrates armature 10, and vibrating of armatiu'e 10 reduces the effective direct current in relay 24: and this reduction of the effective direct current in relay 24:, allows polarized armature 30 to be held in its right-hand position thereby causing the magnet valve circuit to be complete. Stated briefly, this current in the running rails produces in the cab a proceed indication.

Agaimassume that the train enters block B from the right and that block C is occupied. In this condition, track relay 54: will be open and rails 55 and 56 of block B are supplied with only the three volts of secondary 63. The flow of alternating current from. transformer secondary 63, when the rails are shunted by the wheels and axles of the train, will be relatively small due to the low voltage-and to the fact that transformer secondary 63 is made aconstant current transformer. There will not therefore be induced in coil 1 suflicient current to affect 5 to a degree where the polarized armature will be held in its right-hand p sition, but instead the direct current in the relay circuit will be at once increased to approximately 1.0. This value of current in relay 24, will swing polarized armature 30 to the left-hand position,therebyrupturing the magnet valve circuit withthe resultant display of a danger indication and application of the air brakes.

Again let us assume that one train enters block B while block C is clear and that be fore it has traversed the entire length of block- B, a second train enters block B from the right. Now while relay 54 is closed and rails 55 and 56 of block B are supplied with 520 volts, the current will be shunted by the wheels and axles of the first train and there will be no current flowing under coil 1 of the second train. Therefore there will be displayed in the cab of the second train. a danger indication.

Should a train enter block B under a proceed indication and then, while it is traversing block B, block G suddenly becomes occupied, there will be at once displayed in the cab a danger indication, because relay 54 will drop and the current in rails 55 and 56 will be decreased from that supplied by secondary 57 to that of secondary 63. The current supplied by secondary 63 is not sutficient to properlv atl'ect translating device 5.

Likewise if a train enters block B under a danger indication and as it is slowly traversing block B block C suddenly becomes clear, then upon the picking up of relay 54, aproceed indication will in'u'nediately be displayed in the cab.

Should. battery 21 become weakened or the continuity of the relay circuit of the vehicle become broken so that polarized armature 30 could not be actuated in the proper manner, then neutral armature 28 will drop to open the magnet valve circuit at contact point 27. This arrangement is supplied so that a closed circuit principle is maintained.

In Figure 4- is shown a second form of train apparatus. Translating device 5 is what is commercially known as an audion and, is an ordinary exhausted bulb, in which there are three elements, filament F, grid G, and plate P. These elements are so arranged that grid G is between filament F and plate P. The filament F is kept incandescent by battery 80, connected to filament F by wires 81 and 82. The grid G is connected to coil 1, while the other terminal of coil 1 is connected to one terminal .of filament F.

The relay circuit is as follows: battery 83, wire 84, coil of the relay 24, wire 85, plate P, filament F, wire 86 back to battery 83. The magnet valve circuit is as follows: battery 80, wire 87, contact point 27, neutral armature 28, connection 29, polarized armature 30, contact point 31, wire 88, coil of magnet valve 33, wire 89 and 81.

It is well. known that, with a cold filament in an audion bulb, the resistance between plate P and. filament F is very high in which case very little current will flow in the relay circuit, while with a hot filament the resistance between the plate and filament will be relatively low. Now with filament F kept incandescent and grid G at zero potential, a steady current will flow in the relay circuit to energize relay 24;. The value of current under this condition of a hot filament and zero potential grid G is, let us say, one. It is also well known that a small potential on the grid G will very greatly affect the electrons reaching plate P and will therefore greatly affect current flowing in the relay circuit.

\Vhen there is an induced-currentgenerated in coil 1 by current in the rails, it will flow along wire 90, gridG, filament F, wire 91, condenser 7, wire 92 back to coil 1. This induced current being alternating the potential of grid G will be varied from plus to minus, and after a few oscillations the condenser ischarged and the grid assumes a negative potential. with respect to the filament.

l/Vith grid G at zero potential the value of the current in relay circuit is, as stated above, of the value of one. With the potential of grid G made first plus then minus and finally rendered negative by the induced-cin'rent generated in coil 1. the current in the relay circuit will be made to fluctuate between a maximum and a minimum value, and then be reduced to let us say 0.5.

The ustment of relay 24, being the same as that of the first arrangement of vehicle apparatus (Fig. 1) it is clear that with a cur-- rent in the rails there will be generated an in duced-current in coil 1; and polarized armature 80 of relay 24 will be in its right-hand position; and that with no current in the rails to so generate an induced-current in coil 1, polarized armature 30 will be in its left-hand position. Therefore the operation will be the same in the case of Figure 4 as that obtained in the arrangement of Figure 1, the audion acting as a variable resistance or reetifying device.

I claim:

1. A system of train control comprising; a train, traffic rails, a charged direct-current circuit on the train of a given value, a track circuit normally completed through and re sponsive to traflic conditions of the rails, an induced-current circuit and translating device on the train responsive to the track circuit for normally lessening the value of. the direct current and which upon a change in traffic conditions admits of an increase in value of said direct current, and a trafiic governing means held in a normal position so long as the value of the direct current is below a predetermined point and which moves to another position when said value increases above said predetermined point.

2. A system of train control comprising: a train, traflic rails, a charged direct-current circuit on the train of a given value, a track circuit normally completed through and responsive to traffic conditions of the rails, an induced-current circuit and translating device on the train responsive to the track circuit, for normally lessening the value of the direct current and which upon a change in traffic conditions admits of an in'crease in value of said direct current, and a traffic govcrning means held in a normal position so long as the value of the direct current is below a predetermined point and which moves to another position when said value increases above said predetermined point, and means for causing said trafiic governing means to move to said other position upon the rupture of said direct-current circuit.

3. A system of train control including: a trackway arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway source of current, a trackway circuit associated with each block, responsive to traffic conditions of another block and of the block with which it is associated, to continuously control the traincarried circuit through the influence of current flow from said trackway source, and a traincarried traffic-governing translating device, continuously controlled by the train-carried circuit, biased to assume a normal condition when current of a predetermined value is flowing in the train-carried circuit and to assume an abnormal condition when the current flow is either increased or decreased with respect to said predetermined value.

4. A system of train control including: a trackway arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway source of current, a trackway circuit associated with each block, responsive to traffic conditions of another block and of the block with which it is associated, to continuously control the value of current flow in the train-carried circuit thro ugh the influence of current flow from said trackway source, and a train- 'arried trafficgoverning translating device, continuously controlled by the train-carried circuit, biased to assume a normal condition when, current of a predetermined value is flowing in the train carried circuit and to assume an abnormal condition when the current flow is either increased or decreased with respect to said predetermined value.

5. A system of train control including: a trackway arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway source of current, a trackway circuit associated with each block, responsive to traffic conditions of another block and of the block with which it is asso ciated, which when energized by current flow from said trackway source exerts an inductive influence to continuously control the train-carried circuit, and a train-carried traflic-governing translating device, continuously controlled by the train-carried circuit, biased to assume a normal condition when current of a predetermined value is flowing in the train-carried circuit and to assume an abnormalcondition when the current flow is either increased or decreased with respect to said predetermined value.

6. A system of train control including: a trackway arranged in blocks, train, a normally closed train-carried circuit having a current source, a trackway source of current, a trackway circuit associated with each block, responsive to traffic conditions of another block and of the block with whichit is associated, which whenenergized by current flow from said trackway source exerts an inductive influence to continuously control. the value of current flow in the train-carried circuit, and a train-carried traffic-governing translating device, continuously controlled by the traincarr.ied circuit, biased to assume a normal condition when current of a predetermined value is flowing in the train-carried circuit and to assume an abnormal condition when the current flow is either increased or decreased with respect to said predetermined value.

7. A system of train control including: a trackway arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway source of current, a normally closed trackway circuit associated with each block, responsive to traffic conditions of another block and of the block with which it is associated, to continuously control the train-carried circuit through the infiuencejof current flow from said trackway source, and a traincarried traffic-governing translating device, continuously controlled by the train-carried circuit,biased to assume a normal condition when current of a predetermined value is flowing in the train-carried circuit. and to assume an abnormal condition when'the current flow is either increased or decreased with respect to said predetermined value.

8. .A system of train control including: a trackway arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway sourceof current, a normally closedtrackway circuit. associated with each block, responsiveito traliic conditions of anotherblockand of the block with which it is associated, to continuously control the value of current flow inthe train-carried circuitthrough the influence ofcurrent flow from said trackway source, and a train-carried trailic governing translating device, continuously controlled by the train-carried circurt, biased to assume a normal COIldllllOIl when current of a predetermined value is flowing intheatrain-carried circuit and to assumeanabnormalcondition when the current flow iseither increased or decreased with-respect: to said predetermined value.

9. A systemof train control including: a

trackway arrangedinblocks, a train, it normally closed train-carried circuit having a current source, a trackway source of current, a normally closed trackway circuit associated with each block, responsiveto traliic conditionsof anotherblockand of .the block with which it is associated, which when energized by current flow from said trackway source exerts-an inductive influence to continuously control.thetrain-carried circuit, and a traincarried traiTic gOVerningtranslating device, continuously controlled by the train-carried circuit, biased to assume a normal condition when current of a predetermined value is flowingin the train-carried circuit and to assume an abnormal condition when. the current flow is either increased or decreased with respect to said predetermined value.

10. Asystem of train control includin a trackway arranged in blocks, a train, a

normally closed train-carried circuit having a current source, .a trackway source of current,,a-normally closed trackway circuit associated-with each block,.responsive to traffic conditions of another block and of the block with which it is associated, which when energized by current flow from said trackway source exerts an inductive influence to continuously control the value of current How in the train-carried circuit, and a train-carried traffic-governing translating device continuously controlled by the traincarried circuit biased to assume a normal condition when current of a predetermined value is flowing in lLllG-"CftllIl-OitIFlGd circuit and to assume an abnormal condition when the.currentflowiseither increased or decreased with respect to said predetermined value.

11. A system of train control including: atrack composed of trafiic rails arranged in blocks, a train, a normally closed train-carried circuit having a current source, a trackway source of current, a track circuit for each block completed through the tra'flic rails of the block, responsive to tra'flic conditions of another block and of the block with which it is associated, to continuously control. the train-carried circuit through the influence of current flow from said trackway source, and a train-carried traffic-governing translating device, continuously controlled by the train carried circuit, biased'to assume a nori'nal condition when current of a predetermined value is flowing in the train-carried circuit and toassume an abnormal condition when the current flow is either increased or decreased with respect to said predetermined value.

12. A system of train control including: a track composed of trafiic rails arranged in blocks, a train, a normally closed train-can ried circuit having a current source, atrackway source of current,a track circuit for each block completed througlrthe trafiic rails of the block, responsive to trafiic conditions of another block and of the block with which it is associated, to continuously control the value of current flow inithe train-carried circuit through the influence of current flow fromsaid trackway source, and a train-carried traflic-governing translating device, continuously controlled by .thetrain-carried circuit, biased to assume a normal condition when current of apredetermined value is flowing in the train-carried circuit and to assume an abnormal condition when the currentflow is either increased or decreased with respect to said predetermined value.

13. A'system of train control including: a track composed of traflic ralls arranged in blocks, a train, a normally closed train-carrie'd circuitlhaving a current source, a. trackway source of current, a track circuittor each block completed through the traflic rails of the block, responsive to traffic conditions of another block and of the'block with which 'it is associated which when energized by current'fiowfrom said trackway source exerts aninductive influenceto continuously control the train-carried circuit, and a trailicarried tra'fliogoverning translating device, continuously controlled by'the train-carried circuit, biased to assume anormal condition trackway source of current, a track circuit for each block completed through the traflic rails of the block, responsive to traffic conditions of another block and of the block with which it is associated, which when energized by current flow from said trackway source exerts an inductive influence to continuously control the value of current flow in the traincarried circuit, and a train-carried traffic-governing translating device, continuously controlled by the train-carried circuit, biased to assume a normal condition when current of a predetermined value is flowing in the train-carried circuit and to assume an abnormal condition when the current flow is either increased. or decreased with respect to said predetermined value.

15. A system of train control including: a trackway, a train, a normally closed traincarried circuit having a current source, a train'carried traffic-governing translating device, controlled by said circuit, biased to assume a normal condition when current of a predetermined value is flowing in said train'carried circuit and to assume an abnormal condition when current flow either increased or decreased with respect to said predetermined value, another train-carried circuit and a trackway circuit in an inductive relation one to another, and a second train-carried translating device, controlled by the second-mentioned train-carried circuit, to vary the flow of current, in the firstmentioned train-carried circuit, from the predetermined value when no current is flowing in the trackway circuit.

16. A system of train control including: a trackway, a train, a normally closed traincarried circuit having a current source, a train-carried traffic-governing translating device, controlled by said circuit, biased to assume a normal condition when current of a predetermined value is flowing in said traincarried circuit and to assume an abnormal condition when current flow is either in creased or decreased with respect to said predetermined value, another train-carried circuit, a trackway circuit to control said second-mentioned train-carried circuit, and a second train-carried translating device controlling the'first-mentioned train-carried circuit and. controlled by the second-mentioned train-carried circuit.

17. A system of train control including: a trackway, a train, a normally closed traincarried circuit having a current source, a train-carried tratfic-governing translating de vice, controlled by said circuit, biased to assume a normal condition when current of a predetermined value is flowing in said traincarried circuit and to assume an abnormal condition when current flow is either increased or decreased with respect to said predetermined value, a second train-carried translating device to control the train-carried circuit, another train-carried circuit to control the second-mentioned translating device, and a trackway circuit which when energized exerts an inductive influence to control the secondanentioned train-carricd circuit.

18. A system of train control including: a traekway, a train, a normally closed traincarried circuit having a current source, a train-carried traiiic-governing translating device, controlled by said circuit, biased to assume a proceed condition when current of a predetermined value is flowing in said traincarried circuit and to assume a restrictive condition when current flow either increased or decreased with respect to said pre determined value, another train'carried circuit and a trackway circuit in an inductive relation one to another, and a second traincarried translating device, controlled by the secondmentioned train-carried circuit, to vary the flow of current, in the first-mew tioned train-carried circuit, from the predetermined value when no current is flowing in the trackway circuit.

19. A system of train control including: a trackway, a traekway circuit, a train, a closed train-carried circuit including a source of current to supply a current of a given value,

and train-carried means to normally estalo- J lish a predetermined lower value of current flow in said train-carried circuit in response to acurrent flow in the trackway circuit.

20. A system of train control including: a trackway arranged in blocks, a trackway circuit associated with each block and responsive to trafiic conditions of another block, a

train, a closed train-carried circuit including a source of current to supply a current of a given value and train-carried means to normally establish a predetermined lower value of current flow in said train-carried circuit in response to a current flow in the trackway circuit.

21. A system of train control including: a traffic track composed oi rails arranged in blocks, a track circuit normally completed through the rails of the trailic track of a block and responsive to tratlic conditions oi another block and 01' the block with which it is associated, a train, a closed train-carried circuit including a source of current to sup ply a current of a given value, and train-can ried means to normally establish a predetermined lower value of current flow in said train-carried circuit in response to a current flow in the track rails of the block through which the train is traveling.

22. A system of train control including: a trackway, a trackway circuit, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and train-carried means to establish a predetermined lower value oi? current flow in said train-carried circuit in response to a.

proceed trafiic condition of said trackway circuit.

23. A system of train control including: a trackway arranged in blocks, a trackway circuit associated with each block and responsive to traffic conditions or another block, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and train-carried means to estab lish a predetermined lower value of current flow in said train-carried circuit in response to a proceed traflic condition of said trackway circuit.

24- A system of train control including: a trackway, a trackway circuit, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and a train-carried translating device con trolled by the trackway circuit and controlling the train-carried circuit to normally establish a predetermined lower value of current flow in said train-carried circuit in response to a current flow in the trackway circuit.

25. A system of train control including: a trackway arranged in blocks, a trackway circuit associated with each block and responsive to trafiic conditions oi another block, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and a train-carried translating device controlled by the trackway circuit and controlling the train-carried circuit to normally establish a predetermined lower value of current flow in said train-carried circuit in response to a current flow in the trackway circuit.

26. A system of train control including: a traflic track composed of rails arranged in blocks, a track circuit normally completed through the rails of the traflic track of a block and responsive to trafiic conditions of another block and of the block with which it is associated, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and a traincarried translating device controlled by the track circuit and controlling the train-carried circuit to normally establish apredetermined lower value of current flow in said train-carried circuit in response to a current flow in the track rails of theblock through which the train is traveling.

27. A system of train control including: a trackway, a train, a train-carried circuit including a source of current to supply a current flow of a given value, a trackway circuit, a second train-carried circuit and a translating device responsive to current which normally flows in the trackway circuit to lessen the value of current flow in the firstmentioned train-carried circuit, and a p0larized relay on the train influenced by said first-mentioned train-carried circuit to open a circuit in response to an increase in value,

above, said lessened value otthe current flow in said I first-mentioned train-carried circuit.

28. V A system of 'train control including: traflic'rails arranged in blocks, a trackcircuit for each block including the rails and a track relay,-two trackway sources of current for each block, one source capable of supplying current to control both the trackrelay and the train'and the other source capable of supplying current to control the track relay only, trackway means toconnect said first source to .thetrack circuit only under favorable traffic conditionsand to connect said second source to the-track circuit onlyunder adverse traffic conditions, anda circuit and translatingmeans on the train responsive to the current supplied by the first-mentioned source but not-thatsupplied by the secondmentioned source.

29. The combination of a controlling-circuit including asource of current of a. given characteristic, a controlled circuit having'a flovvot current of a differentcharacteristic and of a given value, an intermediate circuit and atranslating device responsive to a current flow in said controlling circuit to lessen. the value of the current-flow in said controlled circuit, and a polarized relay influenced by said controlled circuit. to change the position of its armature in response to a change in value of the current flow insaid controlled circuit.

30. In combination: a controlling circuit including a source of alternating current, a controlled circuit having a flow of direct current of a given value, an intermediate circuit and translating device responsive to a flow of alternating current in the controlling circuit tolessen the value otthedirect current flowing in the controlled circuit, and a polarized relay controlled by said controlled circuit by having the position of its armature reversed by the change from the given to the lesser value. of the directcurrent flowing in the controlled circuit.

31. A system of train control including:

.traflic. rails arranged inblocks, a track circuit for each block includingv the rails and a track relay, two trackwaysources ofalternating current for each block, one source capable of supplying current to control both the track .relay and the train and the other source capable of supplying current to control the track relay only, trafiic controlled means to connect either one or the other of said sources to the track circuit at the exit end of said block, and

.a circuit and translatingmeans on the train a train-carried means to normally establish tained at an increased or decreased valuewith respect to said predetermined value, and a trackway circult WhlCll when energized by a current which normally flows in said traclc way circuit exerts an influence to maintain the current flowing in saidtrain-carried circuit at the predetermined value.

34:. A system of train control including: a trackway, a train, a train-carried circuit including a pick-up coil, a condenser and the grid-filament path of an electron tube, a

trackway circuit, having a source of current, arranged in an inductive relation with the pick-up coil to thereby inductively cause the grid to assume a negative potential with re" spect to the filament of said electron tube when a current flows in the traclrway circuit, a-

charged train-carried circuit including a source of current and the 'ilate-fllament path of said electron tube, and having a flow cit current of a given value, but which flow is maintained at a lesser value so long as the grid is maintained negative by a flow of tracliway circuit current.

35. A system of train control. including: a trackway, a train, a train-carried circuit including a condenser and the grid-filament path of an electron discharge device in series, a trackway circuit, means for creating a charge on the condenser that renders the grid at a negativepotential with respect to the filament in response to a current flow in the trackway circuit, and which permits the condenser to become discharged and thus the negative potential of the grid removed upon an interruption of the current flowing in the trackway circuit, and a second train-carried circuitincluding the plate-filament path of the electron discharge device having a flow of current of a given value, which flow is lessened in value when the grid is rendered negative by the charged condenser and which then reverts to its given value when denser becomes discharged.

36. A system of train control including: a trackway, a trackway circuit having a source of current, a train, a train-carried circuit having a current flow of a given value, and a second train-carried circuitincluding a rectifylng detector to normally lessen the value or the current flowing 1n the first train-car the con-.

ried circuit in response to a current flow in the traclrway circuit.

37. A system of train control including: a. tii'aclrway, a trackway circuit having a source of current, a train, a train-carried circuit having a current source, a train-carried trafficgoverning translating device biased to close another circuit when current of a predetermined value flowing in said train-carried circuit and to open said other circuit When the current flow is increased with respect to said predetermined value, and a train-carried rectifying detector responsive to the influence oi current which normally flows in the track Way circuitto thereby normally decrease the flow of current in the train-carried circuit to said predetermined value.

38. A system of train control including: a trackway, a train, a normally closed traincarried circuit having a current source, a train-carried traflic governing translating device, controlled by said circuit, to assume a clear indication condition when current of a predetermined value is flowing in said traincarried circuit and to assume a restrictive indication condition when current flow is either increased or decreased with respect to said predetermined value, another train-carried circuit, a traclrway circuit invan inductive relation to said second-mentioned train-carried circuit, and a second train-carried translating device controlling the first-mentioned train-carried circuit and controlled by the second train-carried circuit.

89. A system of train control including: a trackway, a trackway circuit, a train, a closed train-carried. circuit including a source of current to supply a current of a given value, and a train-carried means to establish under proceed traffic conditions a predetermined lower value of current flow in said traincarried circuit in response to a current flowing in the trackway circuit.

110. A system of train control including: a traclmvay, a trackway means to exert an inductive influence, a train, a closed traincarried circuit including a source of current to supply a current of a given value, and a train-carriedmeans to establish a predetermined lower value of current flow in said traincarried circuit in response to an inductive influence exerted by said trackway means under proceed traffic conditions.

41. A system of train control including: a trackway, a train, a closed train-carried circuit having a current source, a train-carried trafiic-governing translating device controlledby said train-carried circuit, biased to assume a clear indication condition when a current of a predetermined value is flowing in said train-carried circuit and to assume a restrictive indication condition when the current flow is either maintained at an increased or decreased value with respect to said predetermined value, and a trackway circuit which when energized by the current which flows in said trackway circult under clear trailic conditions exerts an influence to maintain the current flowing in said traincarried circuit at the predetermined value.

42. A system of train control including: a trackway, a trackway circuit, having a source of current, a train, a train-carried circuit ing a pick-up coil in an inductive relation to the trackway, that controls, under clear traffic, conditions, the potential of the grid with respect to the filament to thereby lessen the value of the current flow in the plate-filament circuit in response to a current induced in the pick-up coil, and atrachi-Jay circuit having a current flow, under clear traiiic conditions, to induce a current in the pick-up coil.

44:. A system of train control including: a track'way, a train, an electron tube, on the train, having tilarient, plate and grid elements, a plate-filament circuit including a source of current to supply a current of a given value, a grid-filament circuit, including a pick-up coil in an inductive relation to the trackway, that controls, under clear trafiic conditions, the potential of the grid with respect to the filament to thereby lessen the" value of the current flow in the plate-filament circuit in response to a current induced in the pick-up coil, a trackway circuit having a current flow, under clear traific conditions,

to induce a current in the pick-up coil, and

a train-governing translating device under the control of the current flowing in the platefilament circuit to assume a given position when the current in the plate-filament circuit is lessened in value as a result oi current induced in the pick-up coil and to assume a second given position when the current in the plate-filament circuit is increased from the lesser to the given value as a result of no current induced in the pick-up coil.

45. A system of train control including: a trackway arranged in blocks, a trackway circuit associated with each block and responsive to trafiic conditions of another block, a train, a closed train-carried circuit including a source of current to supply a current of a given value and train-carried means to establish a predetermined lower value of currentilow insaid traiircarried circuit in response to a current flow in the trackway circuit under proceed traffic conditions.

46. A system of train control including: a

'trafic track composed of rails arranged in blocks, a track circuit normally completed through the rails the traiiic track of a block and responsive to'traific conditions 01 another block and of the block with which it is associated, a train, a closed train-carried circuit including a source of current to supply a current of a given value, and train-car ried means to establish under proceed traiiic conditions a predetermined lower value of current flow in sai train-cerrie-d circuit in response to a current flow in the track rails of the block through which the train trav cling,

Signed at Pittsburgh, in the county of Allegheny, and State of Pennsylvania, this 7th day of Nov, 1918.

ABBA G. \VILLI-AMSON; 

